diff options
Diffstat (limited to 'Lib/concurrent/futures/thread.py')
| -rw-r--r-- | Lib/concurrent/futures/thread.py | 20 |
1 files changed, 5 insertions, 15 deletions
diff --git a/Lib/concurrent/futures/thread.py b/Lib/concurrent/futures/thread.py index be79161..2aa4e17 100644 --- a/Lib/concurrent/futures/thread.py +++ b/Lib/concurrent/futures/thread.py @@ -13,19 +13,6 @@ import threading import weakref import os -# Workers are created as daemon threads. This is done to allow the interpreter -# to exit when there are still idle threads in a ThreadPoolExecutor's thread -# pool (i.e. shutdown() was not called). However, allowing workers to die with -# the interpreter has two undesirable properties: -# - The workers would still be running during interpreter shutdown, -# meaning that they would fail in unpredictable ways. -# - The workers could be killed while evaluating a work item, which could -# be bad if the callable being evaluated has external side-effects e.g. -# writing to a file. -# -# To work around this problem, an exit handler is installed which tells the -# workers to exit when their work queues are empty and then waits until the -# threads finish. _threads_queues = weakref.WeakKeyDictionary() _shutdown = False @@ -43,7 +30,11 @@ def _python_exit(): for t, q in items: t.join() -atexit.register(_python_exit) +# Register for `_python_exit()` to be called just before joining all +# non-daemon threads. This is used instead of `atexit.register()` for +# compatibility with subinterpreters, which no longer support daemon threads. +# See bpo-39812 for context. +threading._register_atexit(_python_exit) class _WorkItem(object): @@ -197,7 +188,6 @@ class ThreadPoolExecutor(_base.Executor): self._work_queue, self._initializer, self._initargs)) - t.daemon = True t.start() self._threads.add(t) _threads_queues[t] = self._work_queue |